test.js

var mode = arguments[0]
//var mode = "es5";

function es6(a, b, c) {
  return Math.max(...[a, b, c]);
}

function es5(a, b, c) {
  return Math.max.apply(null, [a, b, c]);
}

function benchmark(f) {
  var start = Date.now();
  for (var i = 0; i < 1000000; i++) {
    f(1, 2, 3);
  }
  var end = Date.now();
  return (end - start);
}

var f = (function () {return this})()[mode];

print('benchmarking...');
print(f);

benchmark(f);
benchmark(f);
benchmark(f);
print(benchmark(f) + ' ms per 1000000 iterations');